/
kern_time.c
1805 lines (1599 loc) · 43 KB
/
kern_time.c
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/* $NetBSD: kern_time.c,v 1.215 2022/06/26 22:31:58 riastradh Exp $ */
/*-
* Copyright (c) 2000, 2004, 2005, 2007, 2008, 2009, 2020
* The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christopher G. Demetriou, by Andrew Doran, and by Jason R. Thorpe.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_time.c 8.4 (Berkeley) 5/26/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_time.c,v 1.215 2022/06/26 22:31:58 riastradh Exp $");
#include <sys/param.h>
#include <sys/resourcevar.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/vnode.h>
#include <sys/signalvar.h>
#include <sys/syslog.h>
#include <sys/timetc.h>
#include <sys/timex.h>
#include <sys/kauth.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <sys/cpu.h>
kmutex_t itimer_mutex __cacheline_aligned; /* XXX static */
static struct itlist itimer_realtime_changed_notify;
static void ptimer_intr(void *);
static void *ptimer_sih __read_mostly;
static TAILQ_HEAD(, ptimer) ptimer_queue;
#define CLOCK_VIRTUAL_P(clockid) \
((clockid) == CLOCK_VIRTUAL || (clockid) == CLOCK_PROF)
CTASSERT(ITIMER_REAL == CLOCK_REALTIME);
CTASSERT(ITIMER_VIRTUAL == CLOCK_VIRTUAL);
CTASSERT(ITIMER_PROF == CLOCK_PROF);
CTASSERT(ITIMER_MONOTONIC == CLOCK_MONOTONIC);
#define DELAYTIMER_MAX 32
/*
* Initialize timekeeping.
*/
void
time_init(void)
{
mutex_init(&itimer_mutex, MUTEX_DEFAULT, IPL_SCHED);
LIST_INIT(&itimer_realtime_changed_notify);
TAILQ_INIT(&ptimer_queue);
ptimer_sih = softint_establish(SOFTINT_CLOCK | SOFTINT_MPSAFE,
ptimer_intr, NULL);
}
/*
* Check if the time will wrap if set to ts.
*
* ts - timespec describing the new time
* delta - the delta between the current time and ts
*/
bool
time_wraps(struct timespec *ts, struct timespec *delta)
{
/*
* Don't allow the time to be set forward so far it
* will wrap and become negative, thus allowing an
* attacker to bypass the next check below. The
* cutoff is 1 year before rollover occurs, so even
* if the attacker uses adjtime(2) to move the time
* past the cutoff, it will take a very long time
* to get to the wrap point.
*/
if ((ts->tv_sec > LLONG_MAX - 365*24*60*60) ||
(delta->tv_sec < 0 || delta->tv_nsec < 0))
return true;
return false;
}
/*
* itimer_lock:
*
* Acquire the interval timer data lock.
*/
void
itimer_lock(void)
{
mutex_spin_enter(&itimer_mutex);
}
/*
* itimer_unlock:
*
* Release the interval timer data lock.
*/
void
itimer_unlock(void)
{
mutex_spin_exit(&itimer_mutex);
}
/*
* itimer_lock_held:
*
* Check that the interval timer lock is held for diagnostic
* assertions.
*/
inline bool __diagused
itimer_lock_held(void)
{
return mutex_owned(&itimer_mutex);
}
/*
* Time of day and interval timer support.
*
* These routines provide the kernel entry points to get and set
* the time-of-day and per-process interval timers. Subroutines
* here provide support for adding and subtracting timeval structures
* and decrementing interval timers, optionally reloading the interval
* timers when they expire.
*/
/* This function is used by clock_settime and settimeofday */
static int
settime1(struct proc *p, const struct timespec *ts, bool check_kauth)
{
struct timespec delta, now;
/*
* The time being set to an unreasonable value will cause
* unreasonable system behaviour.
*/
if (ts->tv_sec < 0 || ts->tv_sec > (1LL << 36))
return (EINVAL);
nanotime(&now);
timespecsub(ts, &now, &delta);
if (check_kauth && kauth_authorize_system(kauth_cred_get(),
KAUTH_SYSTEM_TIME, KAUTH_REQ_SYSTEM_TIME_SYSTEM, __UNCONST(ts),
&delta, KAUTH_ARG(check_kauth ? false : true)) != 0) {
return (EPERM);
}
#ifdef notyet
if ((delta.tv_sec < 86400) && securelevel > 0) { /* XXX elad - notyet */
return (EPERM);
}
#endif
tc_setclock(ts);
resettodr();
/*
* Notify pending CLOCK_REALTIME timers about the real time change.
* There may be inactive timers on this list, but this happens
* comparatively less often than timers firing, and so it's better
* to put the extra checks here than to complicate the other code
* path.
*/
struct itimer *it;
itimer_lock();
LIST_FOREACH(it, &itimer_realtime_changed_notify, it_rtchgq) {
KASSERT(it->it_ops->ito_realtime_changed != NULL);
if (timespecisset(&it->it_time.it_value)) {
(*it->it_ops->ito_realtime_changed)(it);
}
}
itimer_unlock();
return (0);
}
int
settime(struct proc *p, struct timespec *ts)
{
return (settime1(p, ts, true));
}
/* ARGSUSED */
int
sys___clock_gettime50(struct lwp *l,
const struct sys___clock_gettime50_args *uap, register_t *retval)
{
/* {
syscallarg(clockid_t) clock_id;
syscallarg(struct timespec *) tp;
} */
int error;
struct timespec ats;
error = clock_gettime1(SCARG(uap, clock_id), &ats);
if (error != 0)
return error;
return copyout(&ats, SCARG(uap, tp), sizeof(ats));
}
/* ARGSUSED */
int
sys___clock_settime50(struct lwp *l,
const struct sys___clock_settime50_args *uap, register_t *retval)
{
/* {
syscallarg(clockid_t) clock_id;
syscallarg(const struct timespec *) tp;
} */
int error;
struct timespec ats;
if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0)
return error;
return clock_settime1(l->l_proc, SCARG(uap, clock_id), &ats, true);
}
int
clock_settime1(struct proc *p, clockid_t clock_id, const struct timespec *tp,
bool check_kauth)
{
int error;
if (tp->tv_nsec < 0 || tp->tv_nsec >= 1000000000L)
return EINVAL;
switch (clock_id) {
case CLOCK_REALTIME:
if ((error = settime1(p, tp, check_kauth)) != 0)
return (error);
break;
case CLOCK_MONOTONIC:
return (EINVAL); /* read-only clock */
default:
return (EINVAL);
}
return 0;
}
int
sys___clock_getres50(struct lwp *l, const struct sys___clock_getres50_args *uap,
register_t *retval)
{
/* {
syscallarg(clockid_t) clock_id;
syscallarg(struct timespec *) tp;
} */
struct timespec ts;
int error;
if ((error = clock_getres1(SCARG(uap, clock_id), &ts)) != 0)
return error;
if (SCARG(uap, tp))
error = copyout(&ts, SCARG(uap, tp), sizeof(ts));
return error;
}
int
clock_getres1(clockid_t clock_id, struct timespec *ts)
{
switch (clock_id) {
case CLOCK_REALTIME:
case CLOCK_MONOTONIC:
ts->tv_sec = 0;
if (tc_getfrequency() > 1000000000)
ts->tv_nsec = 1;
else
ts->tv_nsec = 1000000000 / tc_getfrequency();
break;
default:
return EINVAL;
}
return 0;
}
/* ARGSUSED */
int
sys___nanosleep50(struct lwp *l, const struct sys___nanosleep50_args *uap,
register_t *retval)
{
/* {
syscallarg(struct timespec *) rqtp;
syscallarg(struct timespec *) rmtp;
} */
struct timespec rmt, rqt;
int error, error1;
error = copyin(SCARG(uap, rqtp), &rqt, sizeof(struct timespec));
if (error)
return (error);
error = nanosleep1(l, CLOCK_MONOTONIC, 0, &rqt,
SCARG(uap, rmtp) ? &rmt : NULL);
if (SCARG(uap, rmtp) == NULL || (error != 0 && error != EINTR))
return error;
error1 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt));
return error1 ? error1 : error;
}
/* ARGSUSED */
int
sys_clock_nanosleep(struct lwp *l, const struct sys_clock_nanosleep_args *uap,
register_t *retval)
{
/* {
syscallarg(clockid_t) clock_id;
syscallarg(int) flags;
syscallarg(struct timespec *) rqtp;
syscallarg(struct timespec *) rmtp;
} */
struct timespec rmt, rqt;
int error, error1;
error = copyin(SCARG(uap, rqtp), &rqt, sizeof(struct timespec));
if (error)
goto out;
error = nanosleep1(l, SCARG(uap, clock_id), SCARG(uap, flags), &rqt,
SCARG(uap, rmtp) ? &rmt : NULL);
if (SCARG(uap, rmtp) == NULL || (error != 0 && error != EINTR))
goto out;
if ((SCARG(uap, flags) & TIMER_ABSTIME) == 0 &&
(error1 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt))) != 0)
error = error1;
out:
*retval = error;
return 0;
}
int
nanosleep1(struct lwp *l, clockid_t clock_id, int flags, struct timespec *rqt,
struct timespec *rmt)
{
struct timespec rmtstart;
int error, timo;
if ((error = ts2timo(clock_id, flags, rqt, &timo, &rmtstart)) != 0) {
if (error == ETIMEDOUT) {
error = 0;
if (rmt != NULL)
rmt->tv_sec = rmt->tv_nsec = 0;
}
return error;
}
/*
* Avoid inadvertently sleeping forever
*/
if (timo == 0)
timo = 1;
again:
error = kpause("nanoslp", true, timo, NULL);
if (error == EWOULDBLOCK)
error = 0;
if (rmt != NULL || error == 0) {
struct timespec rmtend;
struct timespec t0;
struct timespec *t;
int err;
err = clock_gettime1(clock_id, &rmtend);
if (err != 0)
return err;
t = (rmt != NULL) ? rmt : &t0;
if (flags & TIMER_ABSTIME) {
timespecsub(rqt, &rmtend, t);
} else {
if (timespeccmp(&rmtend, &rmtstart, <))
timespecclear(t); /* clock wound back */
else
timespecsub(&rmtend, &rmtstart, t);
if (timespeccmp(rqt, t, <))
timespecclear(t);
else
timespecsub(rqt, t, t);
}
if (t->tv_sec < 0)
timespecclear(t);
if (error == 0) {
timo = tstohz(t);
if (timo > 0)
goto again;
}
}
if (error == ERESTART)
error = EINTR;
return error;
}
int
sys_clock_getcpuclockid2(struct lwp *l,
const struct sys_clock_getcpuclockid2_args *uap,
register_t *retval)
{
/* {
syscallarg(idtype_t idtype;
syscallarg(id_t id);
syscallarg(clockid_t *)clock_id;
} */
pid_t pid;
lwpid_t lid;
clockid_t clock_id;
id_t id = SCARG(uap, id);
switch (SCARG(uap, idtype)) {
case P_PID:
pid = id == 0 ? l->l_proc->p_pid : id;
clock_id = CLOCK_PROCESS_CPUTIME_ID | pid;
break;
case P_LWPID:
lid = id == 0 ? l->l_lid : id;
clock_id = CLOCK_THREAD_CPUTIME_ID | lid;
break;
default:
return EINVAL;
}
return copyout(&clock_id, SCARG(uap, clock_id), sizeof(clock_id));
}
/* ARGSUSED */
int
sys___gettimeofday50(struct lwp *l, const struct sys___gettimeofday50_args *uap,
register_t *retval)
{
/* {
syscallarg(struct timeval *) tp;
syscallarg(void *) tzp; really "struct timezone *";
} */
struct timeval atv;
int error = 0;
struct timezone tzfake;
if (SCARG(uap, tp)) {
memset(&atv, 0, sizeof(atv));
microtime(&atv);
error = copyout(&atv, SCARG(uap, tp), sizeof(atv));
if (error)
return (error);
}
if (SCARG(uap, tzp)) {
/*
* NetBSD has no kernel notion of time zone, so we just
* fake up a timezone struct and return it if demanded.
*/
tzfake.tz_minuteswest = 0;
tzfake.tz_dsttime = 0;
error = copyout(&tzfake, SCARG(uap, tzp), sizeof(tzfake));
}
return (error);
}
/* ARGSUSED */
int
sys___settimeofday50(struct lwp *l, const struct sys___settimeofday50_args *uap,
register_t *retval)
{
/* {
syscallarg(const struct timeval *) tv;
syscallarg(const void *) tzp; really "const struct timezone *";
} */
return settimeofday1(SCARG(uap, tv), true, SCARG(uap, tzp), l, true);
}
int
settimeofday1(const struct timeval *utv, bool userspace,
const void *utzp, struct lwp *l, bool check_kauth)
{
struct timeval atv;
struct timespec ts;
int error;
/* Verify all parameters before changing time. */
/*
* NetBSD has no kernel notion of time zone, and only an
* obsolete program would try to set it, so we log a warning.
*/
if (utzp)
log(LOG_WARNING, "pid %d attempted to set the "
"(obsolete) kernel time zone\n", l->l_proc->p_pid);
if (utv == NULL)
return 0;
if (userspace) {
if ((error = copyin(utv, &atv, sizeof(atv))) != 0)
return error;
utv = &atv;
}
if (utv->tv_usec < 0 || utv->tv_usec >= 1000000)
return EINVAL;
TIMEVAL_TO_TIMESPEC(utv, &ts);
return settime1(l->l_proc, &ts, check_kauth);
}
int time_adjusted; /* set if an adjustment is made */
/* ARGSUSED */
int
sys___adjtime50(struct lwp *l, const struct sys___adjtime50_args *uap,
register_t *retval)
{
/* {
syscallarg(const struct timeval *) delta;
syscallarg(struct timeval *) olddelta;
} */
int error;
struct timeval atv, oldatv;
if ((error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_TIME,
KAUTH_REQ_SYSTEM_TIME_ADJTIME, NULL, NULL, NULL)) != 0)
return error;
if (SCARG(uap, delta)) {
error = copyin(SCARG(uap, delta), &atv,
sizeof(*SCARG(uap, delta)));
if (error)
return (error);
}
adjtime1(SCARG(uap, delta) ? &atv : NULL,
SCARG(uap, olddelta) ? &oldatv : NULL, l->l_proc);
if (SCARG(uap, olddelta))
error = copyout(&oldatv, SCARG(uap, olddelta),
sizeof(*SCARG(uap, olddelta)));
return error;
}
void
adjtime1(const struct timeval *delta, struct timeval *olddelta, struct proc *p)
{
extern int64_t time_adjtime; /* in kern_ntptime.c */
if (olddelta) {
memset(olddelta, 0, sizeof(*olddelta));
mutex_spin_enter(&timecounter_lock);
olddelta->tv_sec = time_adjtime / 1000000;
olddelta->tv_usec = time_adjtime % 1000000;
if (olddelta->tv_usec < 0) {
olddelta->tv_usec += 1000000;
olddelta->tv_sec--;
}
mutex_spin_exit(&timecounter_lock);
}
if (delta) {
mutex_spin_enter(&timecounter_lock);
/*
* XXX This should maybe just report failure to
* userland for nonsense deltas.
*/
if (delta->tv_sec > INT64_MAX/1000000 - 1) {
time_adjtime = INT64_MAX;
} else if (delta->tv_sec < INT64_MIN/1000000 + 1) {
time_adjtime = INT64_MIN;
} else {
time_adjtime = delta->tv_sec * 1000000
+ MAX(-999999, MIN(999999, delta->tv_usec));
}
if (time_adjtime) {
/* We need to save the system time during shutdown */
time_adjusted |= 1;
}
mutex_spin_exit(&timecounter_lock);
}
}
/*
* Interval timer support.
*
* The itimer_*() routines provide generic support for interval timers,
* both real (CLOCK_REALTIME, CLOCK_MONOTIME), and virtual (CLOCK_VIRTUAL,
* CLOCK_PROF).
*
* Real timers keep their deadline as an absolute time, and are fired
* by a callout. Virtual timers are kept as a linked-list of deltas,
* and are processed by hardclock().
*
* Because the real time timer callout may be delayed in real time due
* to interrupt processing on the system, it is possible for the real
* time timeout routine (itimer_callout()) run past after its deadline.
* It does not suffice, therefore, to reload the real timer .it_value
* from the timer's .it_interval. Rather, we compute the next deadline
* in absolute time based on the current time and the .it_interval value,
* and report any overruns.
*
* Note that while the virtual timers are supported in a generic fashion
* here, they only (currently) make sense as per-process timers, and thus
* only really work for that case.
*/
/*
* itimer_init:
*
* Initialize the common data for an interval timer.
*/
void
itimer_init(struct itimer * const it, const struct itimer_ops * const ops,
clockid_t const id, struct itlist * const itl)
{
KASSERT(itimer_lock_held());
KASSERT(ops != NULL);
timespecclear(&it->it_time.it_value);
it->it_ops = ops;
it->it_clockid = id;
it->it_overruns = 0;
it->it_dying = false;
if (!CLOCK_VIRTUAL_P(id)) {
KASSERT(itl == NULL);
callout_init(&it->it_ch, CALLOUT_MPSAFE);
if (id == CLOCK_REALTIME && ops->ito_realtime_changed != NULL) {
LIST_INSERT_HEAD(&itimer_realtime_changed_notify,
it, it_rtchgq);
}
} else {
KASSERT(itl != NULL);
it->it_vlist = itl;
it->it_active = false;
}
}
/*
* itimer_poison:
*
* Poison an interval timer, preventing it from being scheduled
* or processed, in preparation for freeing the timer.
*/
void
itimer_poison(struct itimer * const it)
{
KASSERT(itimer_lock_held());
it->it_dying = true;
/*
* For non-virtual timers, stop the callout, or wait for it to
* run if it has already fired. It cannot restart again after
* this point: the callout won't restart itself when dying, no
* other users holding the lock can restart it, and any other
* users waiting for callout_halt concurrently (itimer_settime)
* will restart from the top.
*/
if (!CLOCK_VIRTUAL_P(it->it_clockid)) {
callout_halt(&it->it_ch, &itimer_mutex);
if (it->it_clockid == CLOCK_REALTIME &&
it->it_ops->ito_realtime_changed != NULL) {
LIST_REMOVE(it, it_rtchgq);
}
}
}
/*
* itimer_fini:
*
* Release resources used by an interval timer.
*
* N.B. itimer_lock must be held on entry, and is released on exit.
*/
void
itimer_fini(struct itimer * const it)
{
KASSERT(itimer_lock_held());
/* All done with the global state. */
itimer_unlock();
/* Destroy the callout, if needed. */
if (!CLOCK_VIRTUAL_P(it->it_clockid))
callout_destroy(&it->it_ch);
}
/*
* itimer_decr:
*
* Decrement an interval timer by a specified number of nanoseconds,
* which must be less than a second, i.e. < 1000000000. If the timer
* expires, then reload it. In this case, carry over (nsec - old value)
* to reduce the value reloaded into the timer so that the timer does
* not drift. This routine assumes that it is called in a context where
* the timers on which it is operating cannot change in value.
*
* Returns true if the timer has expired.
*/
static bool
itimer_decr(struct itimer *it, int nsec)
{
struct itimerspec *itp;
int error __diagused;
KASSERT(itimer_lock_held());
KASSERT(CLOCK_VIRTUAL_P(it->it_clockid));
itp = &it->it_time;
if (itp->it_value.tv_nsec < nsec) {
if (itp->it_value.tv_sec == 0) {
/* expired, and already in next interval */
nsec -= itp->it_value.tv_nsec;
goto expire;
}
itp->it_value.tv_nsec += 1000000000;
itp->it_value.tv_sec--;
}
itp->it_value.tv_nsec -= nsec;
nsec = 0;
if (timespecisset(&itp->it_value))
return false;
/* expired, exactly at end of interval */
expire:
if (timespecisset(&itp->it_interval)) {
itp->it_value = itp->it_interval;
itp->it_value.tv_nsec -= nsec;
if (itp->it_value.tv_nsec < 0) {
itp->it_value.tv_nsec += 1000000000;
itp->it_value.tv_sec--;
}
error = itimer_settime(it);
KASSERT(error == 0); /* virtual, never fails */
} else
itp->it_value.tv_nsec = 0; /* sec is already 0 */
return true;
}
static void itimer_callout(void *);
/*
* itimer_arm_real:
*
* Arm a non-virtual timer.
*/
static void
itimer_arm_real(struct itimer * const it)
{
/*
* Don't need to check tshzto() return value, here.
* callout_reset() does it for us.
*/
callout_reset(&it->it_ch,
(it->it_clockid == CLOCK_MONOTONIC
? tshztoup(&it->it_time.it_value)
: tshzto(&it->it_time.it_value)),
itimer_callout, it);
}
/*
* itimer_callout:
*
* Callout to expire a non-virtual timer. Queue it up for processing,
* and then reload, if it is configured to do so.
*
* N.B. A delay in processing this callout causes multiple
* SIGALRM calls to be compressed into one.
*/
static void
itimer_callout(void *arg)
{
uint64_t last_val, next_val, interval, now_ns;
struct timespec now, next;
struct itimer * const it = arg;
int backwards;
itimer_lock();
(*it->it_ops->ito_fire)(it);
if (!timespecisset(&it->it_time.it_interval)) {
timespecclear(&it->it_time.it_value);
itimer_unlock();
return;
}
if (it->it_clockid == CLOCK_MONOTONIC) {
getnanouptime(&now);
} else {
getnanotime(&now);
}
backwards = (timespeccmp(&it->it_time.it_value, &now, >));
timespecadd(&it->it_time.it_value, &it->it_time.it_interval, &next);
/* Handle the easy case of non-overflown timers first. */
if (!backwards && timespeccmp(&next, &now, >)) {
it->it_time.it_value = next;
} else {
now_ns = timespec2ns(&now);
last_val = timespec2ns(&it->it_time.it_value);
interval = timespec2ns(&it->it_time.it_interval);
next_val = now_ns +
(now_ns - last_val + interval - 1) % interval;
if (backwards)
next_val += interval;
else
it->it_overruns += (now_ns - last_val) / interval;
it->it_time.it_value.tv_sec = next_val / 1000000000;
it->it_time.it_value.tv_nsec = next_val % 1000000000;
}
/*
* Reset the callout, if it's not going away.
*/
if (!it->it_dying)
itimer_arm_real(it);
itimer_unlock();
}
/*
* itimer_settime:
*
* Set up the given interval timer. The value in it->it_time.it_value
* is taken to be an absolute time for CLOCK_REALTIME/CLOCK_MONOTONIC
* timers and a relative time for CLOCK_VIRTUAL/CLOCK_PROF timers.
*
* If the callout had already fired but not yet run, fails with
* ERESTART -- caller must restart from the top to look up a timer.
*/
int
itimer_settime(struct itimer *it)
{
struct itimer *itn, *pitn;
struct itlist *itl;
KASSERT(itimer_lock_held());
if (!CLOCK_VIRTUAL_P(it->it_clockid)) {
/*
* Try to stop the callout. However, if it had already
* fired, we have to drop the lock to wait for it, so
* the world may have changed and pt may not be there
* any more. In that case, tell the caller to start
* over from the top.
*/
if (callout_halt(&it->it_ch, &itimer_mutex))
return ERESTART;
/* Now we can touch it and start it up again. */
if (timespecisset(&it->it_time.it_value))
itimer_arm_real(it);
} else {
if (it->it_active) {
itn = LIST_NEXT(it, it_list);
LIST_REMOVE(it, it_list);
for ( ; itn; itn = LIST_NEXT(itn, it_list))
timespecadd(&it->it_time.it_value,
&itn->it_time.it_value,
&itn->it_time.it_value);
}
if (timespecisset(&it->it_time.it_value)) {
itl = it->it_vlist;
for (itn = LIST_FIRST(itl), pitn = NULL;
itn && timespeccmp(&it->it_time.it_value,
&itn->it_time.it_value, >);
pitn = itn, itn = LIST_NEXT(itn, it_list))
timespecsub(&it->it_time.it_value,
&itn->it_time.it_value,
&it->it_time.it_value);
if (pitn)
LIST_INSERT_AFTER(pitn, it, it_list);
else
LIST_INSERT_HEAD(itl, it, it_list);
for ( ; itn ; itn = LIST_NEXT(itn, it_list))
timespecsub(&itn->it_time.it_value,
&it->it_time.it_value,
&itn->it_time.it_value);
it->it_active = true;
} else {
it->it_active = false;
}
}
/* Success! */
return 0;
}
/*
* itimer_gettime:
*
* Return the remaining time of an interval timer.
*/
void
itimer_gettime(const struct itimer *it, struct itimerspec *aits)
{
struct timespec now;
struct itimer *itn;
KASSERT(itimer_lock_held());
*aits = it->it_time;
if (!CLOCK_VIRTUAL_P(it->it_clockid)) {
/*
* Convert from absolute to relative time in .it_value
* part of real time timer. If time for real time
* timer has passed return 0, else return difference
* between current time and time for the timer to go
* off.
*/
if (timespecisset(&aits->it_value)) {
if (it->it_clockid == CLOCK_REALTIME) {
getnanotime(&now);
} else { /* CLOCK_MONOTONIC */
getnanouptime(&now);
}
if (timespeccmp(&aits->it_value, &now, <))
timespecclear(&aits->it_value);
else
timespecsub(&aits->it_value, &now,
&aits->it_value);
}
} else if (it->it_active) {
for (itn = LIST_FIRST(it->it_vlist); itn && itn != it;
itn = LIST_NEXT(itn, it_list))
timespecadd(&aits->it_value,
&itn->it_time.it_value, &aits->it_value);
KASSERT(itn != NULL); /* it should be findable on the list */
} else
timespecclear(&aits->it_value);
}
/*
* Per-process timer support.